Variations in plasma protein mass during the menstrual cycle of the chacma baboon (Papio ursinus).

Abstract

SUMMARY 1. Considerable fluctuations in plasma volume and protein mass occur in rhythm with the baboon's menstrual cycle. 2. During the follicular phase the mass of circulating albumin and globulin falls, while the fibrinogen mass increases. In the spayed female baboon oestrogen therapy leads to a similar reduction of albumin and globulin, but following ablation of the sexual skin this effect is greatly diminished. 3. During the initial 2–3 days of the luteal phase the circulating protein mass increases abruptly; the mass of protein simultaneously lost from the perineal swelling exceeds that which appears in the plasma. 4. Displacements in plasma protein of comparable extent have not previously been described in any animal maintained under physiological conditions. The available evidence indicates that these unusual fluctuations in the baboon are related to perineal hypertrophy and involution; the nature of this relationship is discussed.