Download Control of Follicle Stimulating Hormone (FSH) Secretion in the Male

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3. MYOCARDIAL NECROSIS INDUCED BY
ANGIOTENSIN II
D. KREMER, J. J. BROWN, A. F. LEVER, G. LINDOP,
J. J. MORTON and J. I. S. ROBERTSON
M.R.C. Blood Pressure Unit, and Department of
Pathology, Western Infirmary, Glasgow GIl 6NT
In a previous study (Gavras et al., 1971, Lancet, ii, 19)
it was shown that the administration of angiotensin
II can cause focal myocardial necroses in the rabbit.
These experiments have been extended by infusing
angiotensin II intravenously into rabbits for periods
up to 24 h at graded doses, arterial plasma angiotensin
II concentration being estimated before, and at intervals during, each infusion. Control animals were infused with saline. Post-mortem, the extent of the
cardiac lesions was assessed histologically by a system
of scoring.
The severity of the induced lesions was shown to
be related to the plasma angiotensin II levels attained
during infusion. Myocardial necroses in some animals
occurred at plasma angiotensin II concentrations
known to occur clinically in man.
4. CONTROL OF FOLLICLE STIMULATING
HORMONE (FSH) SECRETION IN THE MALE:
SITE OF ACTION OF INHIBIN
F. J. BRAMBLE, L. E. HOUGHTON, SHEILA S. ECCLES,
M. A. F. MURRAY and H. S. JACOBS
Leeds General and Bradford Royal Infirmary and St
Mary's Hospital Medical School, London, W.2
Previous studies have indicated that the secretion of
FSH in the male is controlled partly by androgens
and partly by some non androgenic testicular hormone(s)-generally termed inhibin-which is related
specifically to spermatogenesis. The chemical nature
of this compound is as yet unknown.
In an attempt to understand how this compound
modulates FSH secretion we have measured sperm
count (SC), serum testosterone (T), luteinizing hormone (LH) and FSH and the response to exogenous
gonadotrophin releasing hormone (GnRH) in twentyfour adults who had surgical correction of bilateral
cryptorchidism in childhood. In those with normal
SC, T, LH and FSH, the response to GnRH was
normal; in those with aspermia, low T and elevated
basal LH and FSH, the response to GnRH was
exaggerated. By contrast inpatients with oligospermia
or aspermia, raised FSH but normal LH and T, in
whom a specificdeficiencyof inhibin may be presumed,
the response to GnRH of, FSH but not of LH was
exaggerated.
We conclude that inhibin modulates the secretion
of FSH by an interaction with the pituitary response
to GnRH rather than by an action on the hypothalamus.
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5. AUTOMATED RADIOIMMUNOASSAY OF
PLASMA OESTRIOL: UNEXPECTED PROBLEMS
M. G. R. HULL and P. P. MONRO
Department of Obstetrics and Gynaecology, St Mary's
Hospital, London, W.2
(Introduced by H. S. JACOBS)
A method of suitable speed and throughput (120
samples daily) has been developed to assay pregnancy,
plasma unconjugated oestriol (E 3) concentration,
employing a specific antiserum (rabbit anti-Ej-fcarboxymethyl-oxime-BSA, 1/60000) supplied by
Professor R. Scholler, and 3H.E 3 (53·1 Ci/mM) as
label. The useful range is 20-200 pg, equivalent to
2-20 ngjml plasma. The precision of the assay at
3 ng/ml is ±4%. Preliminary mean values obtained
in normal pregnancy at 25 and 40 weeks' gestation
are 3·5 and 12·8 ng/ml.
Ether extracts of 0·1 ml plasma are assayed employing automatic dispensers. High precision associated
with the automated method revealed systematic
errors otherwise undetectable because of the random
errors associated with manual techniques. The major
problem observed was a temperature-dependent
instability of the ammonium sulphate precipitate,
which resulted in an apparent increase of free labelled
hormone, possibly due to dissociation of the antigenantibody complex. One consequence of this effect was
a spurious increase of plasma E 3 values of up to 50%.
Attempts to reduce scintillation fluid volume were
unsuccessful. Presumably due to the polarity of E 3
a large excess (30: 1) of a toluene-based mixture was
required. Moreover ammonium sulphate caused instability of more expensive one-phase systems.
6. THYROID FUNCTION AFTER MEDICAL
AND SURGICAL TREATMENT OF THYROTOXICOSIS AND NON-TOXIC NODULAR
GOITRE
N. W. OAKLEY, R. D. SIMPSON, F. M. BROOKE, D.
BURNETT, T. F. WOODS, N. J. GRIFFITHS, R. GULIN
and R. S. MURLEY
The Alexander Simpson Laboratory for Metabolic
Research, St Mary's Hospital, London, W.2, and St
Albans City Hospital, Normandy Road, St Albans,
Herts.
A high proportion of patients treated for thyrotoxicosis by thyroidectomy or radioactive iodine
developed elevated TSH levels while clinically euthyroid and in the presence of normal thyroid function
judged by other test criteria. The significance of this
finding: is uncertain and it is not clear whether it
represents a state of compensated hypothyroidism or
early thyroid deficiency,requiringreplacement therapy.
Plasma TSH has been measured in 136 patients
treated for thyroid disease between 1956 and 1972,
subdivided into patients treated surgically for (a)