NUTRITIONAL EFFECTS 



675 



1939), unchanged (,]\Iarrian and Parkes, 

 1929; Pomerantz and Mulinos, 1939; Mad- 

 dock and Heller, 1947; Meites and Reed, 

 1949; Blivaiss, Hanson, Rosenzweig and 

 McNeil, 1954), or increased (Rinaldini, 

 1949; Vanderlinde and Westerfield, 1950). 

 An increase in pituitary gonadotrophin was 

 evident when hormone content was related 

 to milligrams of tissue (Meites and Reed, 

 1949). Thus, the hormone release mecha- 

 nism may fail in starvation, and eventually 

 gonadotrophin production will be reduced 

 to a minimum (]\laddock and Heller, 1947). 



Gonadectomy of fully fed rats is followed 

 by an increase in hypophyseal gonado- 

 trophin content. Chronic starvation, how- 

 ever, prevented the anticipated changes in 

 the pituitary gland following gonadectomy 

 in 8 of 12 female rats (Werner, 1939). On 

 the other hand, if adult female rats were 

 subjected to 14 days of reduced feeding 

 1 month after ovariectomy, no change in 

 the elevated gonadotrophin levels was noted 

 (Meites and Reed, 1949). In contrast, 

 Gomez-Mont (1959) observed above normal 

 urinary gonadotrophins in many meno- 

 pausal and postmenopausal women despite 

 undernutrition. 



It is apparent that uniformity of opinion 

 as to how starvation influences hypophyseal 

 gonadotrophin content has not been at- 

 tained. Several explanations can be given for 

 the discrepancies. (1) There have been un- 

 fortunate variations in experimental design. 

 IVIaddock and Heller (1947) starved rats 

 for 12 days, whereas Rinaldini (1949) used 

 a low calorie diet of bread and milk for 

 30 days. Other variations in feeding have 

 included feeding one-half the intake re- 

 quired for growth (Mulinos and Pomerantz, 

 1941b I, regimens of full, one-half, one- 

 ciuarter, and no feeding for 7 and 14 days 

 (Meites and Reed, 1949), and feeding in- 

 adequate amounts of a standard rat diet 

 for 1 to 4 months (Werner, 1939). (2) 

 Hypophyseal implants and anterior pitui- 

 tary extracts should not be compared, for 

 variable gonadotrophin production may fol- 

 low implantation procedures, depending on 

 whether necrosis or growth occurs (Mad- 

 dock and Heller, 1947). (3) There has been 

 an insufficient standardization of experi- 

 mental materials. The assay animal has 

 usually been the immature female rat, but 



occasionally the immature mouse has been 

 used, and Rinaldini (1949) used the hypo- 

 physectomized rat. 



B. PROTEIN 



The need for specific food elements by 

 the hypophysis warrants consideration, 

 for the hormones secreted by this gland 

 are protein in nature and the amino acids 

 for protein synthesis must be drawn from 

 body sources. However, dietary protein 

 levels can vary from 15 per cent to 30 per 

 cent without influencing hypophyseal gona- 

 dotrophin content in rats (Weatherby and 

 Reece, 1941), but diets containing 80 per 

 cent to 90 per cent of casein increased 

 hypophyseal gonadotrophin (Tuchmann- 

 Duplessis and Aschkenasy-Lelu, 1948). Re- 

 moval of protein from the diet will decrease 

 hypophyseal gonadotrophin content in 

 adult male rats in comparison with pair-fed 

 and ad libitum-ied controls, but the de- 

 crease may or may not be significant in a 

 30-day period; luteinizing hormone (LH) 

 seemed to be initially reduced. Extension of 

 the period of protein depletion another 2 

 months resulted in a significant lowering of 

 hy]iophyseal gonadotrophin levels (Table 

 12.4) (Leathern, 1958a). On the other 

 hand, an increased FSH with no decrease 

 in LH activity was observed in the hy- 

 pophyses of adult female rats following 

 30 to 35 days of protein depletion (Srebnik 

 and Nelson, 1957). The available data in- 

 dicate that not only may a sex difference 

 exist, but also that species may differ; resti- 

 tution of gonadotrophin in the discharged 

 rabbit pituitary was not influenced by in- 



TABLE 12.4 



Influence of a protein-free diet on hypophyseal 



gonadotrophin content 



(From J. H. Leathern, Recent Progr. Hormone 



Res., 14, 141, 1958.) 



L^ntreated recipient ovarian weight = 15.4 mg. 

 * PFD = Protein-free diet. 



