Effect of Chronic Inanition on the Gonadotrophic Content of the Pituitary Gland

Abstract

Chronic or acute inanition interrupts the sexual cycle in the albino rat, and is associated with regressive changes in the ovaries. Similar effects have been described in other animals, and ' war amenorrhea ' and sterility are well known to occur among severely malnourished women. The decreased amount of gonadotrophins in the urine of these women and the fact that oestrus can be re-established in underfed animals by either pituitary or chorionic gonadotrophins suggests that anoestrus is not due to primary ovarian dysfunction but to lack of gonadotrophic hormones. This view is supported by various authors, but surprisingly enough only a few of them have endeavoured to measure the actual gonadotrophic power of the anterior lobe during inanition, and this only by the implantation method, which is liable to considerable experimental error as shown by the discrepancies in the results.In the present work, after verification of the oestrus-inhibiting effect of inanition and the sensitivity of the ovary in the strain of rat used to gonadotrophic hormones, saline extracts of the anterior lobes of the pituitary glands of severely underfed rats were injected subcutaneously in hypophysectomized young rats. The effect on ovarian weight was compared with that of the same dose of normal anterior lobe extracts.Parabiosis between undernourished and normally fed rats was carried out, in an attempt to re-establish oestrus by passage of the circulating gonadotrophins from the normal to the starved animal. EXPERIMENTAL Experiment 1. Interruption of oestrous cycle by malnutrition Fifteen mature virgin female rats, with an average weight of 146 g., were isolated in individual cages and fed a restricted balanced diet of bread and milk that provided approximately 14 calories per day, until 30-40 % of their initial weight had been lost (mean loss 36 %). At this stage they were killed, and histological sections of the ovaries were compared with those of ten normal controls.Before the commencement of the experiment, vaginal smears were taken for 7 days while the animals were on stock diets to ensure that they had normal oestrous cycles. After the beginning of caloric restriction, vaginal smears of six animals were examined daily for 30 days. ResultsOestrous cycle. Table 1 shows that, with the exception of rat no. 6, all animals had normal cycles to the 15th day. Irregular and weak oestrus then appeared, until permanent anoestrus was established. Interruption of the sexual cycle was complete in all animals examined from the 21st day onwards.

Infertility in Mice Caused by Fasting at About the Time of Mating

“…Earlier workers 394 T. J. McClure (Marrian & Parkes, 1929;Werner, 1939;Pomerantz & Mulinos, 1939;Rinaldini, 1949) …”

Modification of the Oestrous Cycle of the Underfed Rat Associated With the Time of Feeding

“…The establishment of lengthened oestrous cycles and the subsequent cessation of cyclic activity in rats by dietary restriction has been demonstrated many times (Mulinos & Pomerantz, 1940;Rinaldini, 1949). Oestrous activity may be resumed in a group of such non-cycling rats when they are subjected to the stimulus of constant illumination (Piacsek & Meites, 1965) and the long irregular cycles of underfed rats become more normal in the presence of the male (Cooper & Haynes, 1967).…”

Urinary gonadotrophin excretion in patients with ulcerative colitis and Crohn's disease treated with A.C.T.H. and corticosteroids.

“…It is now well established that a marked degree of gonadal atrophy may occur as a result of malnutrition in various animal species, including rats and guinea-pigs, despite the fact that the gonadotrophins are present in the pituitary gland in normal or even in increased amounts. It is also known that the gonadal atrophy which accompanies severe malnutrition may be rapidly corrected on the resumption of a normal diet (Meites, 1953;Meites and Reed, 1949;Rinaldini, 1949;Pearse and Rinaldini, 1950; see also Leathem, 1961;Chester Jones and Ball, 1962, for reviews). Various explanations can be suggested for these findings, including storage and subsequent release of gonadotrophic hormones, alterations in their rate of production following refeeding and changes in the hypothalmic control of the anterior pituitary gland.…”