Polymorphism C242T in the Cyp19 gene in meat sheep

Abstract The objective of this study was to evaluate the frequency of C242T polymorphism on the aromatase gene and the allelic and genotypic frequency of these variants in sheep belonging to four breed groups. Blood samples were collected from 187 animals of four breed groups: Dorper, Santa Inês, Texel and White Dorper, originated from herds in the region of Maringá/PR, Brazil. The genomic DNA was extracted using alkaline extraction, with subsequent amplification of the fragments via PCR with specific primer. The samples resulting from amplification were subjected to digestion process using the Dpn II restriction enzyme and to polyacrylamide gel electrophoresis 10.0% and stained with silver nitrate. Three distinct genotypes were observed: homozygous (CC), heterozygous (CT) and homozygous for no cut (TT). The resulting data were analyzed using the POPGENE software with 5% significance. Genotypic frequencies among the breed groups were: Texel (CC - 0.426; CT - 0.511; TT - 0.064), Dorper (CC - 0.073; CT - 0.732; TT - 0.439), White Dorper (CC - 0.021; CT - 0.255; TT - 0.723) and Santa Inês (CC - 0.115; CT - 0.462; TT - 0.423).(AU)

Resumo O objetivo deste trabalho foi avaliar as frequências alélicas e genotípicas do polimorfismo do C242T no gene da aromatase em ovinos pertencentes a quatro grupos raciais. Foram coletadas amostras de sangue de 187 animais de quatro grupos raciais: Dorper, Santa Inês, Texel e White Dorper, provenientes de rebanhos da região de Maringá, PR - BR. O DNA genômico foi extraído utilizando o método de extração alcalina, com posterior amplificação dos fragmentos via PCR com primer específico. As amostras resultantes da amplificação foram submetidas ao processo de digestão com auxilio da enzima restrição Dpn II e submetido à eletroforese em gel de poliacrilamida de 10,0% e corado nitrato de prata. Foram observados três genótipos distintos: Homozigoto (CC), heterozigoto (CT) e homozigoto para não corte (TT). Os dados resultantes foram analisados utilizando o software POPGENE com significância de 5%. As frequências genotípicas entre os grupos raciais foram: Texel (CC - 0,426; CT - 0,511; TT - 0,064), Dorper (CC - 0,073; CT - 0,732; TT - 0,439), White Dorper (CC - 0,021; CT - 0,255; TT - 0,723) e Santa Inês (CC - 0,115; CT - 0,462; TT - 0,423).(AU)

Alginate hydrogel matrix stiffness influences the in vitro development of caprine preantral follicles.

This study examined caprine follicular development in different concentrations of alginate matrix to determine the optimal conditions for culture. Caprine preantral follicles were cultured in a two-dimensional system (control) or a three-dimensional encapsulated system in 0.25%, 0.5%, or 1% alginate (ALG 0.25, ALG 0.5, and ALG 1, respectively). A higher percentage of morphologically normal follicles developed in ALG 0.5 and ALG 1 than in ALG 0.25 or the control (P < 0.05). The rate of antrum formation, however, was higher in ALG 0.25 than in ALG 0.5 and ALG 1 conditions (P < 0.05), but similar to the control. Follicles cultured in ALG 0.25 had higher growth rates and meiotic resumption than those cultured in ALG 0.5, ALG 1, or the control (P < 0.05). Moreover, follicles cultured in ALG 0.25 had higher levels of estradiol and progesterone than those cultured in ALG 0.5, ALG 1, or the control, as well as higher levels of CYP19A1 and HSD3B mRNA. In conclusion, a three-dimensional system that uses ALG 0.25 fosters the in vitro development of caprine preantral follicles and increases the rate of meiotic resumption.

The effects of insulin and follicle-simulating hormone (FSH) during in vitro development of ovarian goat preantral follicles and the relative mRNA expression for insulin and FSH receptors and cytochrome P450 aromatase in cultured follicles.

The actions of different concentrations of insulin alone or in combination with follicle-stimulating hormone (FSH) were evaluated by in vitro follicular development and mRNA expression of cytochrome P450 aromatase (CYP19A1) and as receptors for insulin (INSR) and FSH (FSHR) from isolated, cultured goat preantral follicles. Goat preantral follicles were microdissected and cultured for 18 days in the absence or presence of insulin (5 and 10 ng/ml or 10 µg/ml) alone or in combination with FSH. After 18 days, the addition of the maximum concentration of insulin to the culture medium reduced follicular survival and antrum formation rates significantly compared to the other treatments. However, when FSH was added to the culture medium, no differences between these two parameters were observed. Preantral and antral follicles from the fresh control as well as from all cultured follicles still presented a normal ultrastructural pattern. In medium supplemented with FSH, only insulin at 10 ng/ml presented oocytes with higher rates of meiosis resumption compared to control, as well as oocytes in metaphase II. Treatment with insulin (10 ng/ml) plus FSH resulted in significantly increased levels of INSR and CYP19A1 mRNA compared to that with other treatments. In conclusion, 10 ng/ml insulin associated with FSH was more efficient in promoting resumption of oocyte meiosis, maintaining survival, stimulating follicular development, and increasing expression of the INSR and CYP19A1 genes in goat preantral follicles.

The Bidder's organ of the toad Rhinella arenarum (Amphibia, Anura). Presence of steroidogenic enzymes.

The Bidder's organ (BO) of male true toads of Bufonidae family is located in the anterior pole of the testis and it has been compared to a rudimentary ovary because of the presence of previtellogenic follicles. In some species, BO remains in both sexes, while in others only adult males preserve the structure. Several studies suggest that the development of BO is inhibited by the differentiation of the corresponding gonad. The purpose of this study is to describe morphological and histological variability of the BO of Rhinella arenarum and also analyze its steroidogenic capacity. Observations indicate that although most bidderian follicles are in pre vitellogenesis, there are others in early or late vitellogenesis. Moreover, we found that BOs weight was significantly lower in males during the pre-reproductive period and that there is no significant correlation between the weights of BO and the adjacent testis. We also analyzed the presence of steroidogenic enzymes using immunohistochemistry. Results indicate that all the follicles were immunoreactive with the antibody against aromatase, while only few of them were positive for the cytochrome P450 side-chain cleavage. Furthermore, activities of 3ß-hydroxysteroid dehydrogenase/isomerase, cytochrome P450 17-hydroxylase, C17,20-lyase and aromatase were detected by the transformation of radioactive substrates into products. Taken together, these results confirm the steroidogenic capacity of the BO in adult males of R. arenarum.

The interaction between aromatase, metalloproteinase 2,9 and CD44 in breast cancer.

OBJECTIVE: This study intends to verify the expression levels and correlation of aromatase, matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9) and CD44 in ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDC) when both are found in the same breast. METHODS: One hundred and ten cases were evaluated by tissue microarray (TMA) and immunohistochemically screened with anti-aromatase polyclonal antibodies, anti-MMP-2 monoclonal antibodies, anti-MMP-9 polyclonal antibodies and anti-CD44 monoclonal antibodies. RESULTS: Aromatase was expressed in IDC and DCIS in 63 (57.3%) and 60 (67%) of the cases respectively; MMP-2 was similarly expressed in IDC and DCIS in 15 (13.60%) cases; MMP-9 was positively expressed in IDC and DCIS in 83 (75.50%) and 82 (74.50%) cases, respectively; CD44 was positively expressed in IDC and DCIS in 49 (44.50%) and 48 (42.60%) of the cases, respectively; all of them were highly correlated (p<0,001). The correlation analysis found positive, statistically significant correlation, in IDC between aromatase and MMP-2 (p<0.001) and between aromatase and MMP-9 (p=0.034). Positive correlation between aromatase and MMP-2 (p<0.001) and between MMP-9 and CD44 (p=0.030) were found in DCIS. CONCLUSION: These results allow us to conclude that aromatase through local estrogen synthesis in breast tissue plays an important role in breast carcinogenesis, mainly influencing MMP-2 and MMP-9 which are important participants in tumor cell invasion and dependence of their connection to CD44 for action.

The interaction between aromatase, metalloproteinase 2,9 and cd44 in breast cancer / A interação entre aromatase, metalloproteinase 2, 9 e cd44 no câncer de mama

OBJECTIVE: This study intends to verify the expression levels and correlation of aromatase, matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9) and CD44 in ductal carcinoma in situ (DCIS) and infiltrating ductal carcinoma (IDC) when both are found in the same breast. METHODS: One hundred and ten cases were evaluated by tissue microarray (TMA) and immunohistochemically screened with anti-aromatase polyclonal antibodies, anti-MMP-2 monoclonal antibodies, anti-MMP-9 policlonal antibodies and anti-CD44 monoclonal antibodies. RESULTS: Aromatase was expressed in IDC and DCIS in 63 (57.3 percent) and 60 (67 percent) of the cases respectively; MMP-2 was similarly expressed in IDC and DCIS in 15 (13.60 percent) cases; MMP-9 was positively expressed in IDC and DCIS in 83 (75.50 percent) and 82 (74.50 percent) cases, respectively; CD44 was positively expressed in IDC and DCIS in 49 (44.50 percent) and 48 (42.60 percent) of the cases, respectively; all of them were highly correlated (p<0,001). The correlation analysis found positive, statistically significant correlation, in IDC between aromatase and MMP-2 (p<0.001) and between aromatase and MMP-9 (p=0.034). Positive correlation between aromatase and MMP-2 (p<0.001) and between MMP-9 and CD44 (p=0.030) were found in DCIS. CONCLUSION: These results allow us to conclude that aromatase through local estrogen synthesis in breast tissue plays an important role in breast carcinogenesis, mainly influencing MMP-2 and MMP-9 which are important participants in tumor cell invasion and dependence of their connection to CD44 for action.

OBJETIVO: O objetivo desse estudo é verificar as expressões e correlações da aromatase, metalloproteinase 2 da matriz (MMP2), metalloproteinase 9 da matriz (MMP-9) e CD44 no carcinoma ductal in situ (CDIS) e carcinoma ductal infiltrativo (CDI) quando ambos estão presentes simultaneamente na mesma mama. MÉTODOS: Foram avaliados 110 casos pelo método de tissue microarray (TMA) e através da utilização de anticorpos policlonais antiaromatase, anticorpos monoclonais anti-MMP-2, anticorpos policlonais anti-MMP-9 e anticorpos monoclonais anti-CD44. RESULTADOS: A aromatase estava expressa de forma positiva no CDI e CDIS em 63 (57,3 por cento) e 60 (67 por cento) casos, respectivamente. A expressão de MMP-2 estava expressa de forma positiva em 15 (13,6 por cento) casos tanto no CDI, quanto no CDIS. A expressão da MMP-9 estava expressa de forma positiva em 83 (75,5 por cento) e 82 (74,5 por cento) casos de CDI e CDIS, respectivamente. A expressão de CD44 estava expressa de forma positiva em 49 (44,5 por cento) e 48 (42,6 por cento) casos de CDI e CDIS, respectivamente. Todos eles apresentando alta correlação (p<0,001). Na avaliação de correlação foi encontrada correlação positiva estatisticamente significante no CDI entre aromatase e MMP-2 (p<0,01) e entre aromatase e MMP-9 (p=0,034). Nos casos de CDIS houve correlação positiva estatisticamente significante entre aromatase e MMP-2 (p<0,001) e entre CD44 e MMP-9 (p=0,030). CONCLUSÃO: Após analisarmos os resultados de nosso estudo, podemos concluir que a aromatase, através da síntese de estrogênio local no tecido mamário, desempenha importante papel na carcinogênese mamária, principalmente influenciando a atuação da MMP-2 e da MMP-9, grandes responsáveis pela invasão celular tumoral que, por sua vez, provavelmente dependem de sua ligação a CD44 para poder desempenhar suas funções.

[Aromatase expression in invasive and in situ ductal carcinoma present in the same breast]. / Expressão da aromatase em carcinomas de mama ductais invasivo e in situ presentes na mesma mama.

OBJECTIVE: to evaluate the expression of aromatase in simultaneously invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS). METHODS: forty-five surgical samples were obtained from mastectomy and quadrantectomy with simultaneous IDC and DCIS of stage I and II patients. Aromatase was evaluated using antibodies anti-aromatase and the samples classified in accordance with the number and intensity of stained cells. RESULTS: Aromatase was expressed positively in 32(71%) and negatively in 13(29%) of the cases in the IDC. The same results were obtained in the DCIS showing a perfect positive correlation. In the normal epithelium,aromatase was positive in 19(42.2%) and negative in 26 (57.8%) and a positive correlation, statistically significant was obtained when compared with IDC and DCIS(p<0.01). Concerning the normal stroma, positivity was only 7 (15.5%) showing no correlation with aromatase expression. Aromatase was positive in 36(80%) of the tumor stroma and this result was statistically significant as in the IDC and DCIS. Comparing results of aromatase expression with nuclear grade, histological grade, tumor size and age no difference was found. CONCLUSION: our results demonstrated high correlation between aromatase expression in IDC, DCIS, normal epithelium and tumor stroma showing a possible autocrine and paracrine mechanism of this enzyme in breast cancer.

Expressão da aromatase em carcinomas de mama ductais invasivo e in situ presentes na mesma mama / Aromatase expression in invasive and in situ ductal carcinoma present in the same breast

OBJETIVO: Avaliar expressão da enzima aromatase nos carcinomas de mama ductais invasivos (CDI), in situ (CDIS), no epitélio e estromas adjacentes. MÉTODOS: Foram avaliados 45 espécimes cirúrgicos provenientes de mastectomias e quadrantectomias com CDI e CDIS concomitantes de pacientes com estadios clínicos I e II. A análise da expressão da enzima aromatase foi realizada por meio de anticorpos policlonais antiaromatase e categorização das amostras de acordo com intensidade e número de células coradas. RESULTADOS: Nos 45 casos de CDI a expressão da aromatase foi positiva em 32 espécimes (71 por cento) e negativa em 13 (29 por cento). Nos casos de CDIS, a positividade foi idêntica à observada no CDI, mostrando correlação positiva. No epitélio normal constatou-se expressão positiva em 19 casos (42,2 por cento) e negativa nos outros 26 (57,8 por cento), mostrando correlação positiva estatisticamente (p<0,01), quando comparada com CDI e CDIS. Na análise do estroma normal a expressão da aromatase foi observada em apenas sete (15,5 por cento) dos 45 casos avaliados, não apresentando correlação com nenhuma variável analisada para expressão da aromatase. A presença da aromatase no estroma tumoral foi positiva em 36 casos (80 por cento) e negativa em 9 (20 por cento), mostrando correlação estatisticamente com a expressão no CDI (p<0,01) e no CDIS (p<0,01). Ao se comparar a expressão da aromatase no CDI, CDIS, epitélio normal e estroma tumoral com os graus nuclear e histológico, tamanho tumoral e idade da paciente, não foram encontradas diferenças estatisticamente significantes. CONCLUSÃO: Os resultados revelaram alta correlação entre expressão da aromatase no CDI, CDIS, epitélio normal e estroma tumoral, sugerindo possível mecanismo de ação autócrina e parácrina desta enzima na gênese do câncer de mama.

OBJECTIVE: to evaluate the expression of aromatase in simultaneously invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS). METHODS: forty-five surgical samples were obtained from mastectomy and quadrantectomy with simultaneous IDC and DCIS of stage I and II patients. Aromatase was evaluated using antibodies anti-aromatase and the samples classified in accordance with the number and intensity of stained cells. RESULTS: Aromatase was expressed positively in 32(71 percent) and negatively in 13(29 percent) of the cases in the IDC. The same results were obtained in the DCIS showing a perfect positive correlation. In the normal epithelium,aromatase was positive in 19(42.2 percent) and negative in 26 (57.8 percent) and a positive correlation, statistically significant was obtained when compared with IDC and DCIS(p<0.01). Concerning the normal stroma, positivity was only 7 (15.5 percent) showing no correlation with aromatase expression. Aromatase was positive in 36(80 percent) of the tumor stroma and this result was statistically significant as in the IDC and DCIS. Comparing results of aromatase expression with nuclear grade, histological grade, tumor size and age no difference was found. CONCLUSION: our results demonstrated high correlation between aromatase expression in IDC, DCIS, normal epithelium and tumor stroma showing a possible autocrine and paracrine mechanism of this enzyme in breast cancer.

The effect of oral contraceptives on aromatase expression in the eutopic endometrium of patients with endometriosis.

OBJECTIVE: To determine the effect of oral contraceptives containing gestodene on aromatase expression in the endometrium of patients diagnosed with endometriosis. PATIENTS AND METHODS: Endometrial biopsies were taken at the time of laparoscopy in 40 patients with endometriosis, 16 of whom were using an oral contraceptive containing gestodene at the time of laparoscopy. The remaining 24 patients were receiving no form of treatment for endometriosis. Endometrial biopsies taken from 23 patients with normal echographic signs and no symptoms were used as controls. Aromatase expression was evaluated in endometrial samples using immunohistochemistry. RESULTS: In the untreated, symptomatic endometriosis patients, aromatase expression was detected during the proliferative phase in 92% of cases, while in the symptom-free control patients aromatase was expressed in only 9% of cases. In patients with endometriosis who were using oral contraceptives, there were significantly fewer cases of positive endometria compared with the untreated patients with endometriosis (6%). CONCLUSION: Oral contraceptives containing gestodene are effective in decreasing aromatase expression in the eutopic endometrium of patients with endometriosis.

Effects of maternal undernutrition during lactation on aromatase, estrogen, and androgen receptors expression in rat testis at weaning.

The goal of this study was to evaluate the effects of maternal malnutrition during lactation on serum levels of testosterone and estradiol, testicular testosterone concentration, aromatase, testicular androgen (AR) and estrogen alpha (ERalpha) receptors expression in the pups at weaning. From parturition until weaning, Wistar rats were separated into three groups: (C) control group, with free access to a standard laboratory diet containing 23% protein; protein-energy restricted (PER) group, with free access to an isoenergy and protein-restricted diet containing 8% protein; and energy-restricted (ER) group, receiving standard laboratory diet in restricted quantities, which were calculated according to the mean ingestion of the PER group. All pups were killed at weaning, corresponding to 21 days post partum. Compared with the C group, body weights (C=48 +/- 2.3 g; PER=20 +/- 1.3 g; ER=25.4 +/- 0.9 g; P<0.01) and testicular weights (C=0.15 +/- 0.02 g, PER=0.05 +/- 0.01 g, ER=0.06 +/- 0.02 g, P < 0.001) of both PER and ER groups were lower. However, there was no significant difference in the testicular/body weight ratio in PER and ER groups compared with the C group. The testosterone serum concentration (ng/ml) was significantly higher in the PER group compared with ER and C groups (C=0.09 +/- 0.012; PER=0.45 +/- 0.04; ER=0.15 +/- 0.03, P < 0.01). Testicular testosterone concentration (C=2.1 +/- 0.43; PER=6.5 +/- 0.7; ER=13 +/- 2.3, P < 0.01) was increased in treated groups when compared with controls. The estradiol serum concentration (pg/ml) was lower in both dietary groups (C=74 +/- 4.6; PER=49 +/- 3.2; ER=60 +/- 5.5, P < 0.01). The amounts of aromatase mRNA and ERalpha transcripts were significantly lower (P<0.05) in PER and ER groups; conversely AR (both mRNA and protein) was significantly enhanced (P<0.05) in treated animals. The nutritional state in early phases of development is important since we have demonstrated here that the maternal malnutrition during lactation leads to alterations in estradiol and testosterone serum concentrations, testicular testosterone concentration, AR and ERalpha expression together with a decrease of aromatase expression. All together, these changes of steroid status may be deleterious for future germ cell development and reproductive function of these male pups submitted to early malnutrition.

Development of an experimental ovarian tumor: immunocytochemical analysis.

OBJECTIVE: The aim of the present work was to study whether immunocytochemical parameters present in the normal ovary were altered after tumor development under high gonadotropin levels. METHODS: Ovarian tumors (luteoma): castrated female rats had an ovary grafted into the spleen; tumors were left to develop for 1, 2, 3 or 7 months. The presence of apoptotic cells (TUNEL method) and the expression of proliferating cell nuclear antigen (PCNA), gap junction protein (Cx43), steroidogenic acute regulatory protein (StAR), aromatase and synaptosome-associated protein of 25 kDa (SNAP-25) were determined by immunocytochemistry. Some of these findings were confirmed by RT-PCR (Cx43, StAR, SNAP-25). Inhibin subunit mRNAs were investigated by Northern blot. RESULTS: PCNA staining of tumors was mainly found in granulosa cells of transforming follicles and was absent from luteinized follicles. A nearly complete absence of apoptosis was observed. Cx43 was mainly found in follicles, while it was very weakly expressed or absent in luteinized follicles. StAR protein expression, indicating active steroidogenesis, was demonstrated only in luteinized follicles and in thecal cells, but was absent from granulosa cells. Aromatase immunoreactivity was very intense in granulosa and also present in luteal cells. Membrane-associated and cytoplasmic SNAP-25 immunostaining was determined in patches of endocrine cells in the follicles, as well as in the luteinized follicles. The expression of mRNAs for Cx43, StAR and SNAP-25 (RT-PCR) and inhibin subunits (Northern blots) were confirmed in 1-, 3- and 7-month-old tumors. CONCLUSIONS: These results indicated that luteoma most likely develop from unruptured follicles by hypertrophy and proliferation of follicular cells. Circulating gonadotropins seem to play a fundamental role in maintaining the expression of proteins typically expressed in normal ovary, while avoiding apoptosis in this tissue.

Effects of basic fibroblast growth factor and nerve growth factor on lactate production, gamma-glutamyl transpeptidase and aromatase activities in cultured Sertoli cells.

Sertoli cells are under the control of FSH and androgens and also respond to polypeptidic factors locally produced. Basic fibroblast growth factor (bFGF) and nerve growth factor (NGF) have been proposed to belong to the large set of intratesticular regulators. The aim of the present investigation was to analyze the effects of bFGF and NGF on lactate production, gamma-glutamyl transpeptidase (gamma-GTP) and aromatase activities. Cultured Sertoli cells dose-dependently responded to bFGF by increasing lactate production and gamma-GTP activity under basal conditions. In FSH-stimulated cultures, a synergistic effect of FSH with bFGF for lactate production was observed. NGF did not produce changes in lactate production or gamma-GTP activity at any dose tested. Both peptides decreased FSH-stimulated aromatase activity. These results provide additional evidence for the participation of bFGF and NGF in the complex network of intratesticular regulators. bFGF has pleiotropic effects on Sertoli cell function while the actions of NGF seem to be more limited.

Immunolocalization of cytochrome P450 side chain cleavage, 17-alpha-hydroxylase and aromatase in the ovary of vespertilionid bat (Scotophilus heathi) during different phases of ovulatory delay.

Immunocytochemical localization of steroidogenic enzymes, cytochrome P450 side chain cleavage, 17-alpha-hydroxylase and aromatase, was performed in the ovaries of Scotophilus heathi during reproductive cycle, with reference to the period of delayed ovulation. Moderate immunoreactivity of side chain cleavage enzyme and 17-alpha-hydroxylase was observed mainly in thecal cells and interstitial cells of the ovarian stroma during quiescence. Thecal cells positive for 17-alpha-hydroxylase were found even around the primary follicles. The peak immunoreactivity for all the three enzymes was observed during recrudescence. It coincided with high circulating steroid levels during this period. In the stroma, immunoreactivity for side chain cleavage and 17-alpha-hydroxylase was so extensive that it almost occupied the entire interfollicular area of the ovary. Aromatase immunoreactivity declined, but side chain cleavage enzyme and 17-alpha-hydroxylase remained extensive during the period of delayed ovulation. This suggests a high androgen and low estrogen synthesis during the period of delayed ovulation. There was a marked decline in 17-alpha-hydroxylase and an increase in aromatase immunoreactivity during the preovulatory period, suggesting a decrease in androgen and increase in estrogen synthesis. The results suggest thecal cells and interstitial cells of the stroma as the major site of steroidogenesis in the ovary of S. heathi. Over production of androgen is attributed to the extensive development of 17-alpha-hydroxylase positive interstitial cells in the ovarian stroma, and this may be responsible for delayed ovulation in Scotophilus heathi.

Hormonal and paracrine regulation of gamma-glutamyl transpeptidase in rat Sertoli cells.

The effects of follicle-stimulating hormone (FSH) and testosterone on Sertoli cell gamma-glutamyl transpeptidase (gamma-GTP) activity have been studied in vitro. Addition of FSH to Sertoli cell cultures for 5 days induced stimulation of gamma-GTP activity. No testosterone effect was observed alone or in combination with different doses of FSH. Time course studies for a supramaximal dose of FSH showed that enzyme induction could be achieved after a 48 h stimulation. Furthermore, a gradual stimulation of gamma-GTP activity in response to increasing numbers of germinal cells (GC) added in coculture, was observed. Stimulation was also demonstrated with germinal cell-conditioned medium (GCCM). Stimulatory effects of GC and GCCM were additive with those of FSH, suggesting that different mechanisms were involved.