Lipid content and cryotolerance of in vitro-produced bovine embryos treated with forskolin before vitrification / Acúmulo de lipídios intracitoplasmáticos, desenvolvimento e criotolerância de embriões bovinos produzidos in vitro e tratados com diferentes concentrações de forskolin antes da vitrificação

The aim of the present study was to evaluate the intracytoplasmic lipid content, development and cryotolerance of in vitro-produced bovine embryos treated with different concentrations of forskolin before vitrification. Embryos were produced from abattoir-derived ovaries and allocated into four groups. In the treatment groups, forskolin was added to the in vitro culture medium on Day 6 and incubated for 24 hours in one of the following concentrations: 2.5µM (Forsk 2.5 group), 5.0µM (Forsk 5.0 group) or 10.0µM (Forsk 10.0 group). Embryos from the control group were cultured without forskolin. On Day 7 of culture, the expanded blastocysts were stained with the lipophilic dye Sudan Black B for determination of the intracytoplasmic lipid content or were cryopreserved via the Vitri-Ingá® procedure. Although there were no significant differences (P>0.05) in the blastocyst rates between the Control group (44.9%) and the other treatments, the embryo production was lower (P<0.05) in Forsk 10.0 group (38.8%) compared to Forsk 2.5 (50.5%) and Forsk 5.0 (54.7%) groups. The intracytoplasmic lipid content (expressed in arbitrary units of pixels) in blastocysts from the Control group (1.00±0.03) was similar (P>0.05) to that found in Forsk 2.5 (0.92±0.03) and Forsk 10.0 groups (1.06±0.03) groups; however the lipid accumulation in blastocysts from Forsk 5.0 group (0.82±0.04) was lower than in the Control group (P<0.05). Based on these results, Forsk 5.0 treatment was tested for cryotolerance and it was observed that the blastocoel re-expansion rate evaluated 24 hours after warming was greater (P<0.05) in Forsk 5.0 group (72.2%) compared to the Control group (46.2%). In conclusion, pre-treatment with forskolin at a concentration of 5.0 µM for 24 hours before vitrification is effective in reducing the intracytoplasmic lipid content and, consequently, improves cryotolerance of IVP bovine embryos.(AU)

Os embriões foram produzidos a partir de ovários obtidos em abatedouro e foram alocados em quatro grupos experimentais. Nos grupos tratados, o forskolin foi adicionado ao meio de cultivo in vitro no dia 6 do cultivo e os embriões foram incubados durante 24 horas com uma das seguintes concentrações: 2,5µM (grupo Forsk 2,5), 5,0µM (grupo Forsk 5,0) ou 10,0µM (grupo Forsk 10,0). Os embriões do grupo controle foram cultivados na ausência de forskolin. No dia 7 do cultivo, os blastocistos expandidos foram corados com o corante lipofílico Sudan Black B para a determinação do teor de lípidos intracitoplasmáticos ou foram criopreservados através do protocolo Vitri-Ingá®. Não foi observada diferença significativa (P>0,05) na taxa de produção de blastocistos entre o grupo Controle (44,9%) e os demais tratamentos, todavia observou-se menor produção de embriões (P<0,05) no grupo Forsk 10,0 (38,8%) em comparação com os grupos Forsk 2,5 (50,5%) e Forsk 5,0 (54,7%). A quantidade de lipídeos intracitoplasmáticos do grupo Controle (1,00±0,03) foi semelhante (P>0,05) a dos grupos Forsk 2,5 (0,92±0,03) e Forsk 10,0 (1,06±0,03); no entanto, o acúmulo de lípidos nos blastocistos do grupo Forsk 5.0 (0,82 ± 0,04) foi menor do que no grupo controle (P<0,05). A partir destes resultados, o grupo Forsk 5,0 foi testado quanto à criotolerância e foi observado que a taxa de re-expansão da blastocele 24 horas após o aquecimento foi maior (P<0,05) no grupo Forsk 5,0 (72,2%) quando comparado ao grupo Controle (46,2%). Em conclusão, o pré-tratamento com forskolin na concentração de 5,0 µM durante 24 horas antes da vitrificação foi eficiente para promover a redução da quantidade de lipídeos intracitoplasmáticos e, consequentemente, melhorou a criotolerância de embriões bovinos produzidos in vitro.(AU)

The Labdane Ent-3-Acetoxy-Labda-8(17), 13-Dien-15-Oic Decreases Blood Pressure In Hypertensive Rats / O Labdano Ácido Ent-3-Acetóxi-Labda-8(17), 13-Dieno-15-Óico Reduz Pressão Arterial Em Ratos Hipertensos

Abstract Background: Labdane-type diterpenes induce lower blood pressure via relaxation of vascular smooth muscle; however, there are no studies describing the effects of labdanes in hypertensive rats. Objective: The present study was designed to investigate the cardiovascular actions of the labdane-type diterpene ent-3-acetoxy-labda-8(17), 13-dien-15-oic acid (labda-15-oic acid) in two-kidney 1 clip (2K-1C) renal hypertension. Methods: Vascular reactivity experiments were performed in aortic rings isolated from 2K-1C and normotensive (2K) male Wistar rats. Nitrate/nitrite (NOx) measurement was performed in aortas by colorimetric assay. Blood pressure measurements were performed in conscious rats. Results: Labda-15-oic acid (0.1-300 µmol/l) and forskolin (0.1 nmol/l - 1 µmol/l) relaxed endothelium-intact and endothelium-denuded aortas from both 2K-1C and 2K rats. Labda-15-oic acid was more effective at inducing relaxation in endothelium-intact aortas from 2K pre-contracted with phenylephrine when compared to the endothelium-denuded ones. Forskolin was more potent than labda-15-oic acid at inducing vascular relaxation in arteries from both 2K and 2K-1C rats. Labda-15-oic acid-induced increase in NOx levels was lower in arteries from 2K-1C rats when compared to 2K rats. Intravenous administration of labda-15-oic acid (0.3-3 mg/kg) or forskolin (0.1-1 mg/kg) induced hypotension in conscious 2K-1C and 2K rats. Conclusion: The present findings show that labda-15-oic acid induces vascular relaxation and hypotension in hypertensive rats.

Resumo Fundamento: Diterpenos do tipo labdano induzem uma queda da pressão arterial por meio do relaxamento do músculo liso vascular; todavia, não há estudos que descrevam os efeitos de labdanos em ratos hipertensos. Objetivo: O presente estudo foi desenvolvido para investigar as ações cardiovasculares do labdano ácido ent-3-acetóxi-labda-8(17),13-dieno-15-óico (labda-15-óico) na hipertensão renal dois rins-1 clipe (2R-1C). Métodos: Foram feitos experimentos de reatividade vascular em anéis aórticos isolados de ratos machos 2R-1C e normotensos (2R). A medição de Nitrato/Nitrito (NOx) foi feita nas aortas por meio de ensaio colorimétrico. As medidas de pressão arterial foram feitas em ratos conscientes. Resultados: O ácido labda-15-óico (0,1 - 300 µmol/l) e a forscolina (0,1 nmol/l - 1 µmol/l) relaxaram as aortas com endotélio intacto e as aortas sem endotélio dos ratos 2R-1C e 2R. O labda-15-óico mostrou-se mais eficaz na indução do relaxamento em aortas com endotélio intacto de 2R pré-contraídas com fenilefrina em comparação àquelas sem endotélio. A forscolina mostrou-se mais potente do que o ácido labda-15-óico na indução do relaxamento vascular nas artérias tanto de ratos 2R-1C quanto de ratos 2R. O aumento dos níveis de NOx induzido pelo ácido labda-15-óico foi menor nas artérias de ratos 2R-1C em comparação a ratos 2R. A administração intravenosa de ácido labda-15-óico (0,3-3 mg/kg) ou forscolina (0,1-1 mg/kg) induziu hipertensão em ratos 2R-1C e 2R conscientes. Conclusão: Os presentes resultados mostram que o labda-15-óico induz relaxamento vascular e hipotensão em ratos hipertensos.

Interação entre as vias de sinalização de receptores serotoninérgicos e Β-adrenérgicos em artéria femoral de ratos / Interaction between serotoninergic-and β-adrenergic receptors signaling pathways in rat femoral artery / Interacción entre las vías de señalización de receptores serotoninérgicos y β-adrenégicos en la arteria femoral de ratones

FUNDAMENTO: A doença coronária tem sido amplamente estudada em pesquisas cardiovasculares. No entanto, pacientes com doença arterial periférica (DAP) têm piores resultados em comparação àqueles com doença arterial coronariana. Portanto, os estudos farmacológicos com artéria femoral são altamente relevantes para a melhor compreensão das respostas clínicas e fisiopatológicas da DAP. OBJETIVO: Avaliar as propriedades farmacológicas dos agentes contráteis e relaxantes na artéria femoral de ratos. MÉTODOS: As curvas de resposta de concentração à fenilefrina contrátil (FC) e à serotonina (5-HT) e os agentes relaxantes isoproterenol (ISO) e forskolina foram obtidos na artéria femoral de ratos isolada. Para as respostas ao relaxamento, os tecidos foram contraídos com FC ou 5-HT. RESULTADOS: A potência de classificação na artéria femoral foi de 5-HT > FC para as respostas contráteis. Em tecidos contraídos com 5-HT, as respostas de relaxamento ao isoproterenol foram praticamente abolidas em comparação aos tecidos contraídos com FC. A forskolina, um estimulante da adenilil ciclase, restaurou parcialmente a resposta de relaxamento ao ISO em tecidos contraídos com 5-HT. CONCLUSÃO: Ocorre uma interação entre as vias de sinalização dos receptores β-adrenérgicos e serotoninérgicos na artéria femoral. Além disso, esta pesquisa fornece um novo modelo para estudar as vias de sinalização serotoninérgicas em condições normais e patológicas que podem ajudar a compreender os resultados clínicos na DAP.

BACKGROUND: Coronary heart disease has been widely studied in cardiovascular research. However, patients with peripheral artery disease (PAD) have worst outcomes compared to those with coronary artery disease. Therefore, pharmacological studies using femoral artery are highly relevant for a better understanding of the pathophysiologic responses of the PAD. OBJECTIVE: The aim of this study was to evaluate the pharmacologic properties of the contractile and relaxing agents in rat femoral artery. METHODS: Concentration response curves to the contractile phenylephrine (PE) and serotonin (5-HT) and the relaxing agents isoproterenol (ISO) and forskolin were obtained in isolated rat femoral artery. For relaxing responses, tissues were precontracted with PE or 5-HT. RESULTS: The order rank potency in femoral artery was 5-HT > PE for contractile responses. In tissues precontracted with 5-HT, relaxing responses to isoproterenol was virtually abolished as compared to PE-contracted tissues. Forskolin, a stimulant of adenylyl cyclase, partially restored the relaxing response to ISO in 5-HT-precontracted tissues. CONCLUSION: An interaction between β-adrenergic- and serotoninergic- receptors signaling pathway occurs in femoral artery. Moreover, this study provides a new model to study serotoninergic signaling pathway under normal and pathological conditions which can help understanding clinical outcomes in the PAD.

FUNDAMENTO: La enfermedad coronaria ha sido ampliamente estudiada en las investigaciones cardiovasculares. Sin embargo, los pacientes con enfermedad arterial periférica (EAP), tienen los peores resultados en comparación con aquellos con la enfermedad arterial coronaria. Por tanto, los estudios farmacológicos con la arteria femoral son extremadamente importantes para obtener una mejor comprensión de las respuestas clínicas y fisiopatológicas de la EAP. OBJETIVO: Evaluar las propiedades farmacológicas de los agentes contráctiles y relajantes en la arteria femoral de los ratones. MÉTODOS: Las curvas de concentración-respuesta a los agentes conctráctiles fenilefrina (FE) y a la serotonina (5-HT) y los agentes relajantes isoproterenol (ISO) y forskolina, se obtuvieron en la arteria femoral de ratones ya aislada. Para las respuestas a la relajación, los tejidos fueron contraídos con FE o 5-HT. RESULTADOS: La potencia de clasificación en la arteria femoral fue de 5-HT > FE para las respuestas contráctiles. En los tejidos contraídos con 5-HT, las respuestas de relajación al isoproterenol fueron prácticamente eliminadas en comparación con los tejidos contraídos con FE. La forskolina, un estimulante de la adenilil ciclasa, restauró parcialmente la respuesta de relajación al ISO en los tejidos contraídos con 5-HT. CONCLUSIÓN: Ocurre una interacción entre las vías de señalización de los receptores β-adrenérgicos y serotoninérgicos en la arteria femoral. Además, esa investigación suministra un nuevo modelo para estudiar las vías de señalización serotoninérgicas en condiciones normales y patológicas que puedan ayudar a comprender los resultados clínicos en la EAP.

Effect of TNF-α production inhibitors on the production of pro-inflammatory cytokines by peripheral blood mononuclear cells from HTLV-1-infected individuals

Human T lymphotropic virus type 1 (HTLV-1) is the causal agent of myelopathy/tropical spastic paraparesis (HAM/TSP), a disease mediated by the immune response. HTLV-1 induces a spontaneous proliferation and production of pro-inflammatory cytokines by T cells, and increasing interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) levels are potentially involved in tissue damage in diseases related to HTLV-1. This exaggerated immune response is also due to an inability of the natural regulatory mechanisms to down-modulate the immune response in this group of patients. TNF-α inhibitors reduce inflammation and have been shown to improve chronic inflammatory diseases in clinical trials. The aim of this study was to evaluate the ability of pentoxifylline, forskolin, rolipram, and thalidomide to decrease in vitro production of TNF-α and IFN-γ in cells of HTLV-1-infected subjects. Participants of the study included 19 patients with HAM/TSP (mean age, 53 ± 11; male:female ratio, 1:1) and 18 HTLV-1 carriers (mean age, 47 ± 11; male:female ratio, 1:2.6). Cytokines were determined by ELISA in supernatants of mononuclear cell cultures. Pentoxifylline inhibited TNF-α and IFN-γ synthesis with the minimum dose used (50 µM). The results with forskolin were similar to those observed with pentoxifylline. The doses of rolipram used were 0.01-1 µM and the best inhibition of TNF-α production was achieved with 1 µM and for IFN-γ production it was 0.01 µM. The minimum dose of thalidomide used (1 µM) inhibited TNF-α production but thalidomide did not inhibit IFN-γ production even when the maximum dose (50 µM) was used. All drugs had an in vitro inhibitory effect on TNF-α production and, with the exception of thalidomide, all of them also decreased IFN-γ production.

Role of cGMP and cAMP in the hemodynamic response to intrathecal sildenafil administration

INTRODUCTION: Results from our laboratory have demonstrated that intracerebroventricular administration of sildenafil to conscious rats promoted a noticeable increase in both lumbar sympathetic activity and heart rate, with no change in the mean arterial pressure. The intracerebroventricular administration of sildenafil may have produced the hemodynamic effects by activating sympathetic preganglionic neurons in the supraspinal regions and spinal cord. It is well documented that sildenafil increases intracellular cGMP levels by inhibiting phosphodiesterase type 5 and increases cAMP levels by inhibiting other phosphodiesterases. OBJECTIVE: To examine and compare, in conscious rats, the hemodynamic response following the intrathecal administration of sildenafil, 8-bromo-cGMP (an analog of cGMP), forskolin (an activator of adenylate cyclase), or dibutyryl-cAMP (an analog of cAMP) in order to elucidate the possible role of the sympathetic preganglionic neurons in the observed hemodynamic response. RESULTS: The hemodynamic responses observed following intrathecal administration of the studied drugs demonstrated the following: 1) sildenafil increased the mean arterial pressure and heart rate in a dose-dependent manner, 2) increasing doses of 8-bromo-cGMP did not alter the mean arterial pressure and heart rate, 3) forskolin did not affect the mean arterial pressure but did increase the heart rate and 4) dibutyryl-cAMP increased the mean arterial pressure and heart rate, similar to the effect observed following the intrathecal injection of the highest dose of sildenafil. CONCLUSION: Overall, the findings of the current study suggest that the cardiovascular response following the intrathecal administration of sildenafil to conscious rats involves the inhibition of phosphodiesterases other than phosphodiesterase type 5 that increase the cAMP level and the activation of sympathetic preganglionic neurons.

Impaired beta-adrenergic response and decreased L-type calcium current of hypertrophied left ventricular myocytes in postinfarction heart failure

Infarct-induced heart failure is usually associated with cardiac hypertrophy and decreased beta-adrenergic responsiveness. However, conflicting results have been reported concerning the density of L-type calcium current (I Ca(L)), and the mechanisms underlying the decreased beta-adrenergic inotropic response. We determined I Ca(L) density, cytoplasmic calcium ([Ca2+]i) transients, and the effects of beta-adrenergic stimulation (isoproterenol) in a model of postinfarction heart failure in rats. Left ventricular myocytes were obtained by enzymatic digestion 8-10 weeks after infarction. Electrophysiological recordings were obtained using the patch-clamp technique. [Ca2+]i transients were investigated via fura-2 fluorescence. beta-Adrenergic receptor density was determined by [ H]-dihydroalprenolol binding to left ventricle homogenates. Postinfarction myocytes showed a significant 25 percent reduction in mean I Ca(L) density (5.7 + or - 0.28 vs 7.6 + or - 0.32 pA/pF) and a 19 percent reduction in mean peak [Ca2+]i transients (0.13 + or - 0.007 vs 0.16 + or - 0.009) compared to sham myocytes. The isoproterenol-stimulated increase in I Ca(L) was significantly smaller in postinfarction myocytes (Emax: 63.6 + or - 4.3 vs 123.3 + or - 0.9 percent in sham myocytes), but EC50 was not altered. The isoproterenol-stimulated peak amplitude of [Ca2+]i transients was also blunted in postinfarction myocytes. Adenylate cyclase activation through forskolin produced similar I Ca(L) increases in both groups. beta-Adrenergic receptor density was significantly reduced in homogenates from infarcted hearts (Bmax: 93.89 + or - 20.22 vs 271.5 + or - 31.43 fmol/mg protein in sham myocytes), while Kd values were similar. We conclude that postinfarction myocytes from large infarcts display reduced I Ca(L) density and peak [Ca2+]i transients. The response to Beta-adrenergic stimulation was also reduced and was probably related to Beta-adrenergic receptor down-regulation and not to changes in adenylate cyclase activity

Cyclic AMP increases the survival of ganglion cells in mixed retinal cell cultures in the absence of exogenous neurotrophic molecules, an effect that involves cholinergic activity

Natural cell death is a well-known degenerative phenomenon occurring during development of the nervous system. The role of trophic molecules produced by target and afferent cells as well as by glial cells has been extensively demonstrated. Literature data demonstrate that cAMP can modulate the survival of neuronal cells. Cultures of mixed retinal cells were treated with forskolin (an activator of the enzyme adenylyl cyclase) for 48 h. The results show that 50 æM forskolin induced a two-fold increase in the survival of retinal ganglion cells (RGCs) in the absence of exogenous trophic factors. This effect was dose dependent and abolished by 1 æM H89 (an inhibitor of protein kinase A), 1.25 æM chelerythrine chloride (an inhibitor of protein kinase C), 50 æM PD 98059 (an inhibitor of MEK), 25 æM Ly 294002 (an inhibitor of phosphatidylinositol-3 kinase), 30 nM brefeldin A (an inhibitor of polypeptide release), and 10 æM genistein or 1 ng/ml herbimycin (inhibitors of tyrosine kinase enzymes). The inhibition of muscarinic receptors by 10 æM atropine or 1 æM telenzepine also blocked the effect of forskolin. When we used 25 æM BAPTA, an intracellular calcium chelator, as well as 20 æM 5-fluoro-2'-deoxyuridine, an inhibitor of cell proliferation, we also abolished the effect. Our results indicate that cAMP plays an important role controlling the survival of RGCs. This effect is directly dependent on M1 receptor activation indicating that cholinergic activity mediates the increase in RGC survival. We propose a model which involves cholinergic amacrine cells and glial cells in the increase of RGC survival elicited by forskolin treatment

Atividade dos receptores nucleares dos hormônios tireoideanos e do ácido retinóico 9CIS em diferentes elementos responsivos do DNA / Activity of nuclear receptors of thyroid hormones and of retinoid acid 9CIS in differents elements responsives of DNA

O receptor de hormônio tireoidiano (TR) e o receptor do retinóide X (RXR) fazem parte de uma superfamília de receptores nucleares, que em resposta aos seus respectivos ligantes, atuam como fatores de transcriçäo no DNA. Os receptores nucleares possuem uma estrutura modular e a ligaçäo dos mesmos ao DNA se faz como monômeros ou dímeros através do módulo ligador ao DNA (DBD) que se liga a sequências nucleotídicas específicas do DNA, conhecidas como elementos responsivos hormonais (HRE). TR e RXR se ligam a HREs conhecidos como repetiçöes diretas (DRs) do hexâmero AGGTCA (AGGTCAnAGGTCA). t3 e o ácido 9cis-retinóico se ligam a porçäo carboxi-terminal do TR e RXR respectivamente, ativando a transcriçäo gênica. O TR atua principalmente como homodímero ou heterodímero, ligando-se no último caso ao RXR. Nosso estudo analisou a ligaçäo do TR e do RXR a im grupo de DRs separadas por um número variável de nucleotídeos, de 0 a 6, com o objetivo de estabelecer a importância desses HREs na transcriçäo gênica destes receptores nucleares. Confirmamos através de cultura de células e eletroforese em gel de poliacrilamida que o espaçamento ideal para a resposta do T3 medida pelo TR é de 4 nucleotídeos (DR4). A forscolina, um potencializador da proteína cinase A (PKA), foi capaz de potencializar a resposta transcricional do TR ao T3. O RXR pode atuar como parceiro silencioso de outros receptores nucleares, ou como homodímero em resposta ao ácido 9cis-retinóico. Nossos ensaios de eletroforese demonstraram que o RXR pode se ligar como homodímero näo só ao conhecido elemento responsivo DR1, mas também a DR2, DR3, DR4, DR5 e DR6, numa forma dependente de 9cisRA. Em cultura de células a forscolina demonstrou uma evidente açäo sinérgica do RXR nos elementos DR1 a DR5. Desta forma, demonstramos que homodímeros de RXR podem possuir uma atividade transcricional mais ampla do que se acreditava e verificamos a importância de mecanismos de conversa cruzada entre os receptores nucleares TR eRXR com o sistema de sinalizaçäo via AMP cíclico

Agents that affect cAMP levels or protein kinase A activity modulate memory consolidation when injected into rat hippocampus but not amygdala

Male Wistar rats were trained in one-trial step-down inhibitory avoidance using a 0.4-mA footshock. At various times after training (0, 1.5, 3,6 and 9 h for the animals implanted into the CA1 region of the hippocampus; 0 and 3 h for those implanted into the amygdala), these animals received microinfusions of SKF38393 (7.5 mug/side), SCH23390 (0.5 mug/side), norepinephrine (0.3 mug/side), timolol (0.3 mug/side), 8-OH-DPAT (2.5 mug/side), NAN-190 (2.5 mug/side), forskolin (0.5 mug/side), KT5720 (0.5 mug/side) or 8-Br-cAMP (1.25 mug/side). Rats were tested for retention 24 h after training. When given into the hippocampus 0 h post-training, norepinephrine enhanced memory whereas KT5720 was amnestic. When given 1.5 h after training, all treatments were ineffective. When given 3 or 6 h post-training, 8-Br-cAMP, forskolin, SKF38393, norepinephrine and NAN-190 caused memory facilitation, while KT5720, SCH23390, timolol and 8-OH-DPAT caused retrograde amnesia. Again, at 9 h after training, all treatments were inffective. When given into the amygdala, norepinephrine caused retrograde facilitation at 0 h after training. The other drugs infused into the amygdala did not cause any significant effect. These data suggest that in the hippocampus, but not in the amygdala, a cAMP/protein kinase A pathway is involved in memory cosolidation at 3 and 6 h after training, which is regulated by D1, Beta, and 5HT1A receptors. This correlates with data on increased post-training cAMP levels and a dual peak of protein kinase A activity and CREB-P levels (at 0 and 3-6 h) in rat hippocampus after training in this task. These results suggest that the hippocampus, but not the amygdala, is involved in long-term storage of step-down inhibitory avoidance in the rat.

Effect of different gonadal states on the forskolin stimulated adenylate cyclase activity in rat brain

Forskolin-stimulated adenylate cyclase activity, measured in the hypothalamus and cerebral cortex differs in male and female rats. The gonadal steroid treatment performed induced changes in the studied adenylate cyclase activity probably in relation to the sex of the animals. The stimulated-forskolin adenylate cyclase activity in the hypothalamus from orchidectomized males showed more sensitivity than ovariectomized females. Finally, in male rats, the effects of castration on the hypothalamic enzymatic activity were partially restored by the administration of testosterone dipropionate. On the other hand, estradiol decreased the forskolin-adenylate cyclase activity in the female hypothalamus and cerebral cortex. The results show that the forskolin-stimulated adenylate cyclase activity may be related with the sex and/or the gonadal state of experimental animals.