Hormonal basis of variation in oestrous cyclicity in selected strains of mice

Reproductive hormone secretion and ovarian LH receptor content were studied during the oestrous cycle of mice that differed in fertility after genetic selection. Strain variation in the secretory pattern of progesterone was observed along with differences in the timing and magnitude of prolactin release. Scatchard analysis showed similar affinities of the LH receptor for hCG in strains with increased or decreased reproductive performance, with a single order of binding sites during both pro-oestrus and dioestrus. The number of unoccupied LH receptors during pro-oestrus was greatest in mice with increased reproductive performance. These results provide evidence that trait selection can change gonadotrophin receptor concentration and the dynamics of hormone secretion during the oestrous cycle of the mouse.     

Estrogen-bridged purines: A new series of anti-tumor agents which alter cell membrane properties

An estrogen-bridged adenine derivative was equitoxic to both the P388 murine leukemia and an adriamycin-resistant subline, $\text{P388}\text{ADR}$. The drug rapidly altered several P388 and $\text{P388}\text{ADR}$ membrane properties resulting in impaired nucleoside transport and increased membrane hydrophobicity. Resistance to anthracyclines in $\text{P388}\text{ADR}$ is associated with an operational barrier to drug retention which was reversed by exposure to the estrogen-bridged adenine derivative. These results suggest further exploration of the estrogen-bridged purines as chemotherapeutic agents.