Bioassay of hypothalamic gonadotropin stimulating factor

Zusammenfassung Es wird eine einfache und rasche, die Ovulation induzierende Methode beschrieben, mit welcher sich der das hypothalamische Gonadotrophin stimulierende Faktor bestimmen lässt. Die mit diesem Faktor angereicherten Präparate erhöhten die 20-Hydroxypregn-4-en-3-one-und die Progesteronkonzentrationen im venösen Blut der Ovarien von Kaninchen sowie den Gehalt und die Sekretion von Gonadotrophin von in vitro inkubierten Hypophysen.

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Reported in part at the 6th Pan-American Congress of Endocrinology, October 1965.     

The action of ouabain in promoting the release of catecholamines.

It is suggested that ouabain promotes catecholamine release by causing a rise in intracellular Na+ which, in turn, causes an elevated steady-state level of intracellular Ca2+. It is suggested that the Na+-K+-ATPase is not directly involved in exocytosis at either adrenergic or cholinergic synapses.     

Rebasing the annual mid-year population estimates for England and Wales

The ONS produces mid-year population estimates annually, which are based on updating from the most recent census. Therefore, whenever results become available from a census, a new base is created for the population estimates. This has implications for historic series, which need to be revised to be consistent with both the past and the most recent census. This article describes the methodology that will be used for this rebasing of the mid-year population estimates following the availability of results from the 2001 Census. Census results also provide a unique opportunity to assess the accuracy of the population estimates that are based on the previous census and this article also describes the approach that will be taken to the assessment of accuracy.     

Animal behaviour: use of dung as a tool by burrowing owls

Reports of tool usage by birds tend to be anecdotal as only a few individuals may be involved and the behaviour observed can often be interpreted in other ways. Here we describe the widespread collection of mammalian dung by burrowing owls (Athene cunicularia) and show that they use this dung as a bait to attract dung beetles, a major item of prey. Our controlled investigation provides an unambiguous estimate of the importance of tool use in a wild animal.