The role of the pineal gland in the regulation of LH-release in rats with different types of the anovulatory syndrome.

The effect of different doses of testosterone propionate was investigated in provoking the development of the constant estrous anovulatory (CEA) syndrome in the rat. A direct relationship was observed between the dose of neonatally administered androgen (NA) and the percentage occurrence of this syndrome. Pinealectomy and superior cervical sympathetic ganglionectomy elicited the development of marked thecal luteinization in the NA-CEA rat, but the formation of corpora lutea was limited after these operations. The efficacy of pinealectomy and ganglionectomy in provoking luteinization was inversely related to the dose of testosterone used for neonatal androgenization. The LH-RH sensitivity of the adenohypophysis to release LH was decreased in the NA animals, as well as in the light-induced CEA syndrome (LCE), whereas it was increased in those CEA rats in which this syndrome was provoked by frontal hypothalamic deafferentation (FHD). Pinealectomy and ganglionectomy were able to elicit ovulation and luteinization in the FHD animals, but were ineffective in the LCE and high dose NA rats. The results are discussed in relation to those reported by others, in an attempt to explain the multitude of dissociated effects.