Regional distribution and in vitro secretion of salmon and chicken-II gonadotropin-releasing hormones from the brain and pituitary of juvenile and adult goldfish, Carassius auratus.

The content of salmon (sGnRH) and chicken-II (cGnRH-II) gonadotropin-releasing hormones was measured in discrete brain regions and pituitaries of juvenile and postspawning adult goldfish, using specific radioimmunoassays. In juveniles, the content of both peptides was low. sGnRH was the predominant form in telencephalon-preoptic area (T-POA) (sGnRH:cGnRH-II ratio = 2.06 +/- 0.66) and diencephalon (DIEN) (sGnRH:cGnRH-II ratio = 2.72 +/- 0.32), whereas cGnRH-II was predominant in cerebellum-brain stem (STEM) (sGnRH:cGnRH-II ratio = 0.47 +/- 0.05). Equal amounts of the two peptides were present in pituitary (PIT) (sGnRH:cGnRH-II ratio = 1.04 +/- 0.18). In adults, the content of both peptides in all regions was significantly increased. The increase in sGnRH exceeded that of cGnRH-II in T-POA and PIT, resulting in an increased sGnRH:cGnRH-II ratio in these tissues (T-POA, 3.55 +/- 0.26; PIT, 7.85 +/- 2.28). In DIEN and STEM, the increase in cGnRH-II content equaled or exceeded that of sGnRH; the sGnRH:cGnRH-II ratio was unchanged in STEM (0.39 +/- 0.06) and decreased in DIEN (1.23 +/- 0.13). The secretion of sGnRH and cGnRH-II was investigated under static in vitro incubation conditions. Both forms of the peptide were secreted from T-POA slices and PIT fragments from juvenile and adult fish. Secretion was significantly increased under potassium depolarizing conditions. Secretion of the two peptides was proportional to their content in tissues from both juvenile and adult goldfish.

In vitro release of gonadotropin-releasing hormone from the brain preoptic-anterior hypothalamic region and pituitary of female goldfish.

In vitro release of gonadotropin releasing hormone (GnRH) from slices of the preoptic-anterior hypothalamic (P-AH) region and fragments of the pituitary of goldfish was studied using a static incubation system. Release of GnRH from both tissue preparations was stimulated by depolarizing concentrations of extracellular potassium ions (K+). Other putative secretagogues, calcium ionophore A23187 (1 microM), forskolin (100 microM), and prostaglandin E2 1 microM) also stimulated release of GnRH from both tissue preparations. Omission of Ca2+, or chelating the remaining remaining Ca2+ by EGTA (0.1 mM), abolished the release of GnRH stimulated by high K+ concentrations (60 mM), but did not reduce spontaneous release. Verapamil (1 microM), a voltage-sensitive calcium channel blocker, abolished the release of GnRH stimulated by high K+ or A21387 from both tissue preparations. The GnRH released in vitro from both the P-AH region and pituitary was concentrated by Sep-Pak and then separated by high-performance liquid chromatography. The major peak of the GnRH immunoreactivity was found to coelute with synthetic salmon GnRH [( Trp7,Leu8]-GnRH) and the minor peak with chicken GnRH-II [( Gln8]-GnRH). Dopamine (10 and 100 microM) inhibited GnRH release from both P-AH slices and pituitary fragments, while serotonin (1-100 microM) stimulated release from both. Norepinephrine (10-100 microM) stimulated GnRH release from P-AH slices but not from pituitary fragments. The results demonstrate that the release of GnRH from goldfish P-AH slices and pituitary fragments in vitro in response to various secretagogues and monoamines can be studied using a static incubation system.

Growth hormone-dependent potentiation of gonadotropin-stimulated steroid production by ovarian follicles of the goldfish.

The possible involvement of growth hormone (GH) in the regulation of ovarian function in the goldfish was investigated by determining the effects of common carp GH on steroid production by vitellogenic and preovulatory ovarian follicles incubated in vitro. Carp GH acts in a dose-dependent manner to potentiate the actions of common carp gonadotropin (GtH) on the production of 17 beta-estradiol and testosterone by vitellogenic ovarian follicles and the actions of human chorionic gonadotropin (hCG) on testosterone production by preovulatory ovarian follicles. Carp GH alone had no effect on basal steroid secretion by either class of ovarian follicles. Chum salmon GH but not bovine GH also enhanced carp GtH-induced production of 17 beta-estradiol by vitellogenic ovarian follicles. Common carp prolactin had no effects on basal or GtH-stimulated steroid production by vitellogenic or preovulatory ovarian follicles. The actions of carp GH on preovulatory follicles were not apparent when tested with the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine, suggesting that GH may act to enhance either the formation or actions of cAMP. In summary, these data demonstrate that GH has a direct modulatory effect on GtH-stimulated steroid production and suggest that GH may be an important regulator of follicular development in the goldfish.

Evidence for the involvement of endogenous opioids in the regulation of gonadotropin secretion in male goldfish, Carassius auratus.

The in vivo effects of the opioid receptor antagonist naloxone (NAL) alone, and in combination with des-Gly10[D-Ala6]LHRH ethylamide (LHRH-A) and the dopamine receptor antagonist domperidone (DOM) on serum gonadotropic hormone (GtH) levels in male goldfish, Carassius auratus, were investigated. NAL caused a significant decrease in serum GtH 1 hr following treatment, with a return to control levels by 2 hr. NAL treatment attenuated the stimulation of GtH levels in response to DOM; NAL treatment 2 hr prior to or 2 hr following DOM resulted in a significantly reduced response to DOM. During late recrudescence, NAL pretreatment significantly blocked the stimulatory effects of LHRH-A on serum GtH. During early recrudescence, when LHRH-A alone did not significantly elevate GtH levels, NAL treatment simultaneously with or 1 hr following LHRH-A significantly elevated serum GtH. In DOM-pretreated fish, combined LHRH-A and NAL treatment resulted in a nine-fold increase in serum GtH compared to DOM alone. These data indicate the ability of NAL to both suppress and increase GtH levels in male goldfish. Interactions between NAL, DOM, and LHRH-A suggest that opioids modulate both dopamine and GnRH secretion, and possibly the pituitary sensitivity to GnRH and dopamine, thus affecting GtH levels.

Validation of radioimmunoassay systems for the measurement of 11-keto- and 11 beta-hydroxytestosterone in teleost blood.

Highly specific antisera for 11-keto- and 11 beta-hydroxytestosterone have been raised in sheep. Assay systems for the simultaneous measurement of 11-ketotestosterone, 11 beta-hydroxytestosterone, testosterone, progesterone and estradiol-17 beta were validated for Ictalurus nebulosus plasma and Carassius auratus serum. In males of both species 11-ketotestosterone and testosterone were the major steroids detected. In females, testosterone and estradiol-17 beta were the predominant steroids measured. Data from samples taken at different stages of the annual cycle suggest that seasonal fluctuations in gonadal steroid secretion occur in I. nebulosus and C. auratus.

Use of the Honan intraocular pressure reducer at The Wilmer Institute.

Our technique for the preparation of the patient for cataract surgery is discussed, with description of our use of the Honan intraocular pressure reducer (HIPR). Results of preoperative use of the HIPR in a prospective study of 21 patients and our retrospective experience with over 1,000 patients undergoing cataract surgery (with or without lens implantation) are discussed. The HIPR appears to be a safe and effective means of reducing intraocular pressure preoperatively when used with due care.

Cysteamine reduces serum gonadotropin concentrations in adult male rats.

We have examined the effects of cysteamine on the hypothalamic-pituitary-gonadal axis of the adult male rat. A single subcutaneous injection of cysteamine (300 mg/kg) reduces significantly (p less than or equal to 0.05 serum concentrations of LH, FSH and T. Cysteamine blocked LH secretion induced by castration and administration of naloxone and LHRH. Neither acute nor chronic treatment (7 days) altered the hypothalamic LHRH content. These results suggest that cysteamine acts to reduce pituitary responsiveness to LHRH, resulting in lower mean serum gonadotropin and testosterone concentrations. It is possible, however, that cysteamine acts also at the hypothalamus to reduce LHRH secretion and/or at the testes to reduce testosterone release.

Choroidal ischemia after extracapsular cataract extraction by phacoemulsification.

Three patients developed apparent choroidal ischemia after phacoemulsification. The outer half of the posterior retina appeared white after operation, with confluent lesions in the posterior pole and splotchy white areas in the midperiphery. The separate lesions appeared similar in pattern to the lobular division of the choriocapillaris, and the retinal vessels were not involved. The white lesions resolved in two to three weeks, leaving alterations in the pigment epithelium. Vision was transiently reduced in each eye but returned to a nearly normal level in two of three affected eyes, although paracentral scotomas persisted. In each case of phacoemulsification, the posterior lens capsule was either damaged or was removed. In all three cases, an investigational type of irrigating solution (BSS Plus) containing balanced salt, glutathione, and other constituents was used. Controlled ocular compression was performed before operation using a pneumatic device in two cases. However, the cause of retinal and choroidal damage now described was probably excessively elevated intraocular pressure during the operation.

Hereditary Fuchs' Dystrophy.

We studied 102 individuals from 25 families in which at least one member was known to have Fuchs' endothelial dystrophy. We used slit-lamp examination, corneal pachymetry, and specular microscopy. We also examined pathology records which contained 79 cases of penetrating keratoplasties done solely for phakic Fuchs' dystrophy between 1940 and 1978. Although there was a marked predominance of females in our review of pathology records, our clinical study provided a more even sex distribution. There was a close correlation between the number of expected and observed affected first-degree relatives based on an autosomal-dominant mode of inheritance. We observed a fairly typical corneal pattern, beginning as a circumscribed area of central or paracentral cornea guttata, and thereafter expanding more horizontally than vertically with progression of severity. Fuchs' dystrophy appears to be a true corneal dystrophy with autosomal-dominant inheritance, a high degree of penetrance, and variable expressivity, with generally increased severity among females.

Postoperative inflammatory reactions to intraocular lense sterilized with ethylene-oxide.

Postoperative inflammatory complications after intraocular lens implantation have increased since we have been using lenses manufactured by American companies and sterilized with ethylene-oxide, as compared with lenses from European companies sterilized by sodium hydroxide. The possible sources of this complication are discussed.

Sudden visual loss secondary to an orbital varix.

A 45-year-old man presented with precipitous loss of vision and rapidly changing field defects in one eye. Computerized tomography and B-scan ultrasonography revealed a small orbital mass adjacent to the optic nerve. This was removed via lateral orbitotomy. On pathologic examination it was diagnosed as a small orbital varix. Drs. Frederick C. Blodi and Stephen Trokel comment on the case.