Chronic Treatment With Lh-Rh in Golden Hamsters

Abstract

A 22-month-old girl presented with neck pain and stiffness and magnetic resonance imaging showed an extradural mass extending from C2 through the C4 level with moderate to severe compression of the cord. A left unilateral C2-C4 laminectomy was performed revealing an extradural rubbery tumor; a small biopsy was obtained. Examination of stained tissue revealed the presence of a parasitic worm that was identified as a gravid female Onchocerca lupi. A magnetic resonance imaging at 7 weeks follow-up showed a significantly decreased size of the enhancing lesion and the patient's symptoms gradually resolved. This is the first report of zoonotic O. lupi in the United States. The parasite has been reported in dogs and cats in the western United States, and from people in four cases reported from Europe. A great deal more needs to be learned, including full host range and geographic distribution, before we fully understand O. lupi infections in animals and man.

Effect of very high dose D-leucine6-gonadotropin-releasing hormone proethylamide on the hypothalamic-pituitary testicular axis in patients with prostatic cancer.

“…Potent GnRH-A produce prostatic atrophy and reduction of testosterone levels in a variety of species (38)(39)(40)(41)(43)(44)(45). Reports of these paradoxical actions stimulated several ongoing studies of GnRH-A as potential treatment strategies for androgen-dependent prostatic carcinoma in man (46)(47)(48).…”

Ovarian Gonadotropin-Releasing Hormone Receptors, II. Regulation and Effects on Ovarian Development

“…Loss of gonadotropin receptors and desensitization of gonadal function by exogenous and endogenous gonadotropins have been well documented by a number of laboratories (8,15,16,22). Also, resistance of the pituitary to GnRH has been observed during repeated or constant stimulation with GnRH and its agonist analogs (9,10,18).…”

“…G ONADAL receptor sites for GnRH, 1 recently identified in the luteinized rat ovary (1) and characterized in the preceding paper (2), are responsible for mediating the direct inhibitory effects of GnRH agonists on ovarian function (3)(4)(5)(6). Such direct ovarian effects of GnRH agonists, together with indirect actions exerted via gonadal desensitization by elevation of endogenous gonadotropins (7,8) and pituitary refractoriness (9,10), are responsible for the marked inhibitory effects of GnRH peptides upon reproductive function. The demonstration that GnRH agonists inhibit FSH-induced steroidogenesis in cultured granulosa cells (5) suggests that GnRH receptors are also present in ovarian follicles and are retained during subsequent luteinization.…”

Inhibitory Control of the Pituitary LH Secretion by LH-RH in Male Rats

“…Supraphysiological doses of LH-RH (0.5 -1 qg/rat) can reduce pituitary responsiveness to a test dose of LH-RH in male and female rats (Sandow and Babej, 1973) after chronic treatment for 21 days, and inhibit recovery of spermatogenesis in male hamsters with gonadal atrophy (Sandow and Hahn, 1978). This unexpected effect of LH-RH could be a consequence of direct pituitary inhibition, negative steroid feedback of the testes or down regulation of testicular LH receptors (Auclair et al, 1977).…”

“…Inhibition of LH secretion can be induced in the rabbit by infusion of HCG (Molitch et al, 1976), and in castrate male rats by chronic treatment with a highly active analogue of LH-RH (Sandow et al, 1978a). Treatment with LH-RH in high doses exerts paradoxical antifertility effects in the rat, rabbit and dog Corbin, \911\Rippel andJohnson, 1976,Sandow, 1978;Sandow and Hahn, 1978). In men with psychogenic impotence.…”