Biological potency and radioimmunoassay of canine calcitonin.

Calcitonin (CT) is a major calcitropic hormone. Because of low cross reactivity of canine CT (cCT) in radioimmunoassays (RIA) developed for other species, a homologous RIA is needed. Synthesis of cCT allowed study of its biologic potency using a rat bioassay and its plasma half-life in dogs.

Absorption of hydrophilic and lipophilic compounds through epidermal and subepidermal strata of rat skin in vitro.

The absorption of a model hydrophilic compound (benzoic acid) and a model lipophilic compound [di(2-ethylhexyl)phthalate; DEHP] was measured through separated epidermal membranes and through the residual stripped dermis of rat skin. Absorption was determined using both phosphate buffered saline (PBS) and 50% ethanol/water as the receptor fluid. The rate and extent of DEHP absorption through epidermis was greatly increased (40- to 80-fold) using 50% ethanol/water as receptor fluid compared with using PBS, but with the stripped dermis only a small difference (approximately two- to threefold) was detected.